Joe Pigott netted his third goal in two games as the Hatters secured a 12th victory away from home this season.
Pigott profited from Pelly Ruddock’s flick back before Josh McQuoid doubled the advantage after fantastic work from Pigott, reciprocating McQuoid’s assist from the Oxford trip.
Jack Stacey pulled one back for Carlisle, but the Town hung on to a third successive League Two victory with a resolute defensive display.
The win takes the Hatters above their hosts, although the difference between them and the play-offs remains at six points.
Nathan Jones named an unchanged side from the victory at Oxford in which Pigott, leading the line, scored twice for his first Town goals.
Carlisle started with the majority of possession, failing to test Elliot Justham early on as the Hatters developed into the game from around the 15 minute mark.
Indeed it was the visitors boasting the first chance. Stephen O’Donnell, impressive going forward all evening, unleashed a fantastic 25-yard volley the keeper was forced to tip over following a rebound from a Danny Green corner.
And the Hatters were ahead mid-way through the half, with Green’s neat flick setting Ruddock away down the right hand side, operating behind Pigott as he did last time out. His cross found Pigott in space on the edge of the area, and while the striker had plenty to do, he did it in style with a cool turn and shot to open the scoring.
Pigott was once again proving a handful in attack, but Carlisle came close to equalising when Alex Gilliead’s defence-splitting pass found Alex McQueen, whose cross was begging for a Cumbrian man to touch past Justham.
Alex Lawless, celebrating his 200th Hatters game at Oxford, almost provided some audacious skill to double the advantage. He robbed the ball from a Carlisle player in a dangerous position, lobbing a defender to find Ruddock on the edge of the area, who could only drag his shot wide.
The Town did double their lead just six minutes into the second half though. Fine perseverance from Pigott on the byline saw him attempt two crosses to the box, with the latter causing chaos in the home box which McQuoid benefitted from to tuck home in the far post to reassure the 235 fans in the away end.
Carlisle were not without their chances though, and they should have pulled one back when Jason Kennedy flicked a McQueen cross straight to the path of Jabo Ibehre, who could only touch wide from a yard or two out.
But the Blues halved the deficit just second later, with Stacey running diagonally at the Hatters defence before firing past Justham at the near post to set up a nervy final 30 minutes at Brunton Park.
Captain Alan Sheehan was forced into sound defensive duty on more than one occasion, heading off the line for the first of two occasions from Charlie Wyke’s header beyond Justham.
The Town were doing well to soak up Carlisle pressure while looking to push their visitors on the break, with McQueen posing numerous questions with a series of crosses which Nathan Jones’ side dealt with aptly.
And the Cumbrians felt they had equalised with just ten minutes left on the clock, when Ibehre forced the ball goalwards, only for Sheehan to complete his double to nod off the line and, in the absence of goal-line technology, the assistant referee gave the Hatters the benefit of the doubt.
Substitute Cameron McGeehan had a chance to put the game beyond doubt, but he could only sky a first-time effort over the bar following yet another surging O’Donnell break.
But it proved not to matter for the Town, making this their ninth consecutive League 2 win by a one-goal margin and their third overall.
Hatters: Justham, Potts, O’Donnell, Sheehan, Rea, Lee, Lawless, Ruddock (sub Howells 85), Green (sub McGeehan 69), McQuoid (sub Marriott 90+1), Pigott
Unused subs: King, Benson, Musonda, Banton
Attendance: 3497, with a fantastic 235 backing the Hatters. Thank you for your excellent support!